This invention relates to an improved apparatus for degassing molten metal, and especially to a heated apparatus which obviates the necessity for draining after each use.
An improved method and apparatus for degassing molten metal is disclosed in U.S. Pat. No. 4,177,066 to Joseph A. Clumpner and assigned to the assignee of the instant invention. The disclosure in the aforenoted patent teaches degassing molten metal using an apparatus comprising a swirling tank reactor wherein molten metal is tangentially introduced into the reactor so that the molten metal flows in a swirling rotating fashion as the metal passes from the inlet of the reactor to the outlet thereof. In order to achieve the desired swirling flow of molten metal from the metal inlet to the metal outlet of the reactor, it is required that the metal inlet be positioned with respect to the chamber wall of the reactor in such a manner as to tangentially introduce the liquid into the reactor. In a preferred embodiment, the swirling tank reactor comprises a first elongated substantially cylindrical sidewall portion and a second downwardly converging sidewall portion beneath the first substantially cylindrical wall portion. Fluxing gas inlet nozzles penetrate the converging wall portion at different heights thereof so as to optimize fluxing gas bubble dispersion through the entire melt as it passes from the inlet of the reactor to the outlet thereof. By positioning the nozzles at different heights in the converging wall portion, the fluxing gas nozzles are in turn located at various distances from the center axis of the swirling tank reactor thereby maximizing fluxing gas bubble dispersion. The specific details of the various embodiments of swirling tank reactors and nozzle locations disclosed in U.S. Pat. No. 4,177,066 may readily employ the improved heated apparatus of the present invention and the disclosure of U.S. Pat. No. 4,177,066 is incorporated hereby by reference.
Additional nozzle designs are shown in U.S. Pat. No. 4,392,636 to Joseph A. Clumpner, U.S. Pat. No. 4,494,735 to Robert E. Hershey, and U.S. patent application Ser. No. 833,172, filed Feb. 26, 1986 by Howard A. McDonald (the inventor herein), now U.S. Pat. No. 4,647,018 all of which are assigned to the assignee of the instant case.
A disadvantage of current designs is that the apparatus is not heated which requires draining of the molten metal after each use. The heating of degassing apparatus presents serious potential difficulties in view of the need to maintain careful temperature control and the interrelationship with molten metal flow and fluxing gas. Moreover, it is necessary to provide a system at a low cost and compact design with moderate power demands. It is of course necessary to provide such a system without sacrificing production quality.
Accordingly, it is a principal object of the present invention to provide an improved, heated apparatus for degassing molten metal.
It is a further object of the present invention to provide an apparatus as aforesaid of compact design which efficiently maintains careful temperature control with moderate power demands.
Further objects and advantages of the present invention will appear hereinbelow.